10/16/24, 11:39 BIO 101 - The cell and its
AM environment
THE CELL AND ITS ENVIRONMENT
Environment/nature and state of matter:
Living cells are known to be surrounded by a watery environment.
This may include; (1) Fresh/salt water in which the unicellular
organisms live.
(2) Intercellular fluid that bathes the bodies of the cells of
higher
animals.
The nature of states of matter makes diffusion and osmosis
possible. Matter can be defined as any material that has mass
and occupies space. It includes all living and non-living things
around us. Matter is also made up of tiny particles which may be
molecules or ions and can exist in this form; solid, liquid or gas.
DIFFUSION
Diffusion is a process by which molecules of a substance move
from a region of higher concentration to a region of lower
concentration (through the medium of air or liquid) until
equilibrium is reached. The difference in the concentration of the
substances in the two regions before diffusion occurred is called
concentration/diffusion gradient.
E.g. Kmno4 (Potassium tetraoxomanganate VII) is placed in a
beaker of water and allowed to stand, the purple color of the
Kmno4 will start to spread outward from the crystal. Eventually,
the color spread evenly throughout the medium.
Diffusion is also observed in the spread of odor of perfume
insecticide which is used to spray a room and also in the release
of gases from the anus.
Factors Affecting the Rate of Diffusion
Diffusion is affected by the following factors;
1. Change in temperature: The higher the temperature, the
faster the rate of diffusion.
2. Molecular size: Diffusion increases with decrease in molecular
size.
3. State of matter: Diffusion of gases is much faster than that of
liquid.
about:blan 1/
k 5
, 10/16/24, 11:39 BIO 101 - The cell and its
AM environment
4. Differences in concentration: The greater the
difference in concentration of molecules, the
faster the rate of diffusion.
Importance of diffusion in plants
1. Diffusion aids movement of oxygen produced during
photosynthesis into the atmosphere.
2. Diffusion assists easy movement of carbon (IV)oxide
from the atmosphere into the leaves through the
stomata cell.
3. Diffusion promotes free movement of oxygen needed for
respiration
from the atmosphere into the plant through the stomata cell.
4. Movement of water vapor from the leaves of plants to
the outside through transpiration is by diffusion.
Importance of diffusion in animals
1. Absorption of glucose and other food materials through the
villi of the small intestine is through diffusion.
2. Diffusion aids the exchange of body nutrients in the
placenta from the mother to the developing fetus.
3. Diffusion aids gaseous exchange in many cells and
organisms. For instance, Amoeba takes in oxygen and
gets rid of carbon (IV) oxide by diffusion.
4. Diffusion aids the movement of carbon (IV) oxide from
the lung capillaries into the air sac and vice-versa.
Importance of Diffusion in Living Organisms
1. The movement of carbon (IV) oxide through the stomata
of leaves during the process of photosynthesis.
2. Movement of oxygen into the lungs during respiration.
3. Movement of water vapor out of the leaves in the
process of transpiration.
4. Gaseous exchange in the lungs of mammals.
5. Intake of oxygen and nutrients and the removal of waste
product by the fetus from its mother through the
placenta.
6. Movement of digested and soluble food from the villi of
the small intestine into the lungs.
7. Removal of waste product in small organisms such as amoeba.
about:blan 2/
k 5
AM environment
THE CELL AND ITS ENVIRONMENT
Environment/nature and state of matter:
Living cells are known to be surrounded by a watery environment.
This may include; (1) Fresh/salt water in which the unicellular
organisms live.
(2) Intercellular fluid that bathes the bodies of the cells of
higher
animals.
The nature of states of matter makes diffusion and osmosis
possible. Matter can be defined as any material that has mass
and occupies space. It includes all living and non-living things
around us. Matter is also made up of tiny particles which may be
molecules or ions and can exist in this form; solid, liquid or gas.
DIFFUSION
Diffusion is a process by which molecules of a substance move
from a region of higher concentration to a region of lower
concentration (through the medium of air or liquid) until
equilibrium is reached. The difference in the concentration of the
substances in the two regions before diffusion occurred is called
concentration/diffusion gradient.
E.g. Kmno4 (Potassium tetraoxomanganate VII) is placed in a
beaker of water and allowed to stand, the purple color of the
Kmno4 will start to spread outward from the crystal. Eventually,
the color spread evenly throughout the medium.
Diffusion is also observed in the spread of odor of perfume
insecticide which is used to spray a room and also in the release
of gases from the anus.
Factors Affecting the Rate of Diffusion
Diffusion is affected by the following factors;
1. Change in temperature: The higher the temperature, the
faster the rate of diffusion.
2. Molecular size: Diffusion increases with decrease in molecular
size.
3. State of matter: Diffusion of gases is much faster than that of
liquid.
about:blan 1/
k 5
, 10/16/24, 11:39 BIO 101 - The cell and its
AM environment
4. Differences in concentration: The greater the
difference in concentration of molecules, the
faster the rate of diffusion.
Importance of diffusion in plants
1. Diffusion aids movement of oxygen produced during
photosynthesis into the atmosphere.
2. Diffusion assists easy movement of carbon (IV)oxide
from the atmosphere into the leaves through the
stomata cell.
3. Diffusion promotes free movement of oxygen needed for
respiration
from the atmosphere into the plant through the stomata cell.
4. Movement of water vapor from the leaves of plants to
the outside through transpiration is by diffusion.
Importance of diffusion in animals
1. Absorption of glucose and other food materials through the
villi of the small intestine is through diffusion.
2. Diffusion aids the exchange of body nutrients in the
placenta from the mother to the developing fetus.
3. Diffusion aids gaseous exchange in many cells and
organisms. For instance, Amoeba takes in oxygen and
gets rid of carbon (IV) oxide by diffusion.
4. Diffusion aids the movement of carbon (IV) oxide from
the lung capillaries into the air sac and vice-versa.
Importance of Diffusion in Living Organisms
1. The movement of carbon (IV) oxide through the stomata
of leaves during the process of photosynthesis.
2. Movement of oxygen into the lungs during respiration.
3. Movement of water vapor out of the leaves in the
process of transpiration.
4. Gaseous exchange in the lungs of mammals.
5. Intake of oxygen and nutrients and the removal of waste
product by the fetus from its mother through the
placenta.
6. Movement of digested and soluble food from the villi of
the small intestine into the lungs.
7. Removal of waste product in small organisms such as amoeba.
about:blan 2/
k 5
